1. Field of the Invention
The present invention relates to a driving force transmitting apparatus used for a transfer or a final reduction apparatus.
2. Background Art
A conventional driving force transmitting apparatus is disclosed, for example, in JP-A-2000-065191. FIG. 16 is a sectional view showing a final reduction apparatus as an example of the conventional driving force transmitting apparatus, FIG. 17 is a rear side view of a carrier of the final reduction apparatus, and FIG. 18 is a front side view of a cover of the final reduction apparatus.
As shown in FIG. 16 through FIG. 18, a breather chamber 211 is formed so as to be opposed to coupling surfaces 207 and 209 of carrier 203 and cover 205 of the final reduction apparatus 201. The breather chamber 211 is defined as a space surrounded by outer walls 213, 215 of the carrier 203 and the cover 205 and the ribs 217, 219 thereof. A communication path 221 is formed at a part of the rib 217. Oil paths 227 and 229 located between the ribs 217, 219 and ribs 223,225 formed downward thereof are communicated with the breather chamber 211 through the communication path 221. A partition plate 231 is provided in the oil paths 227 and 229. The partition plate 231 prevents a lubricant oil lifted by a ring gear 233 from flowing from the oil paths 227, 229 into the communication path 221.
The ribs 217 and 219 protrude from insides of the outer walls of the carrier 203 and the cover 205 in a die removing direction. That is, the ribs 217 and 219 extend to the coupling surfaces 207 and 209. The breather chamber 211 is formed to be divided into sides of the carrier 203 and the cover 205, respectively.
Therefore, the carrier 203 and the cover 205 are matched and coupled to each other at the coupling surfaces 207 and 209, and it is possible to easily form the breather chamber 211 over the carrier 203 and the cover 205.
However, in the conventional structure, as the partition plate 231, an L-shaped rectangular coupling portion 231a cannot be formed by a die-casting of the carrier 203 and the cover 205, because the partition plate 231 is perpendicular to the die removing direction so that the partition plate 231 can not be removed from die if the partition plate 231 is integrally formed by the die-casting integrally with the carrier 203 or the cover 205. Accordingly, it is necessary to manufacture the partition plate 231 as a separate member by punching a metallic plate. Therefore, machining, assembly and parts management of the partition plate 231 become complicated, resulting in an increase in production costs. Further, clearance is likely to occur between the partition plate 231, the carrier 203 and the cover 205, wherein it is insufficient in view of preventing lubricant oil from invading the communication path 221.